I have almost 10 GB of incomplete files (mostly music videos) from
now-defunct WinMX P2P file sharing service.  I also have alot of
eDonkey incomplete files as well.
  I am now using eMULE and would like to convert these incomplete
files from WinMX and eDonkey2000 into the 'temp' folder where eMULE
incomplete-but-growing-and listed files are.
  Is there any way I can integrate these 10 GB's of already started
files into a different P2P program than the one they originated in ???

Hi there, the demise of WinMX is due to the folding of Frontcode
Technologies and the closure of the WinMX.com server. This server
provided the IP addresses to WinMX supernodes, thereby allowing
clients entry to the network. With the WinMX.com domain eliminated,
the network collapsed.

Now I'm no expert, but WinMX and ED2K do use different networks,
OpenNap and eDonkey's own network respectively. I'm not sure how
cross-compatible these networks would be, as undoubtably they have
different methods of locating, identifying and downloading files, and
the composition of incomplete files.

Thankfully, some members of the P2P community have taken it upon
themselves to provide another way of connecting to WinMX hosts rather
than through the now dead WinMX.com page.It involves downloading a
file which indexes different winMX hosts for winMX to connect to
without trying to get these hosts from a dead server.

Information on how to do this is available here:

http://www.slyck.com/news.php?story=925

which is where I got a lot of the information for this comment from. 
Hopefully this will be some help to you. I'm sorry I haven't directly
answered the question, but hopefully the method above should allow you
to at least finish your incomplete WinMX downloads.